Answer: E) 8i
Explanation:
By definition, i = sqrt(-1)
Which means,
sqrt(-64) = sqrt(-1*64)
sqrt(-64) = sqrt(-1)*sqrt(64)
sqrt(-64) = i*sqrt(8^2)
sqrt(-64) = i*8
sqrt(-64) = 8i
On the second line, I used the rule sqrt(x*y) = sqrt(x)*sqrt(y). The fourth line used the rule sqrt(x^2) = x when x is nonnegative.
